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LibJS/Bytecode: Implement initial support for super member expressions

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This commit is contained in:
Luke Wilde 2023-05-15 18:45:16 +01:00 • committed by Andreas Kling
parent 00493687f2
commit b15128c45b
5 changed files with 137 additions and 31 deletions
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46
Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
View file

@ -1523,20 +1523,46 @@ Bytecode::CodeGenerationErrorOr<void> CallExpression::generate_bytecode(Bytecode
if (is<NewExpression>(this)) {
TRY(m_callee->generate_bytecode(generator));
generator.emit<Bytecode::Op::Store>(callee_reg);
} else if (is<SuperExpression>(*m_callee)) {
return Bytecode::CodeGenerationError {
this,
"Unimplemented callee kind: SuperExpression"sv,
};
} else if (is<MemberExpression>(*m_callee)) {
auto& member_expression = static_cast<MemberExpression const&>(*m_callee);
// https://tc39.es/ecma262/#sec-super-keyword-runtime-semantics-evaluation
if (is<SuperExpression>(member_expression.object())) {
return Bytecode::CodeGenerationError {
this,
"Unimplemented callee kind: MemberExpression on SuperExpression"sv,
};
// 1. Let env be GetThisEnvironment().
// 2. Let actualThis be ? env.GetThisBinding().
generator.emit<Bytecode::Op::ResolveThisBinding>();
generator.emit<Bytecode::Op::Store>(this_reg);
Optional<Bytecode::Register> computed_property_value_register;
if (member_expression.is_computed()) {
// SuperProperty : super [ Expression ]
// 3. Let propertyNameReference be ? Evaluation of Expression.
// 4. Let propertyNameValue be ? GetValue(propertyNameReference).
TRY(member_expression.property().generate_bytecode(generator));
computed_property_value_register = generator.allocate_register();
generator.emit<Bytecode::Op::Store>(*computed_property_value_register);
}
// 5/7. Return ? MakeSuperPropertyReference(actualThis, propertyKey, strict).
// https://tc39.es/ecma262/#sec-makesuperpropertyreference
// 1. Let env be GetThisEnvironment().
// 2. Assert: env.HasSuperBinding() is true.
// 3. Let baseValue be ? env.GetSuperBase().
generator.emit<Bytecode::Op::ResolveSuperBase>();
// 4. Return the Reference Record { [[Base]]: baseValue, [[ReferencedName]]: propertyKey, [[Strict]]: strict, [[ThisValue]]: actualThis }.
if (computed_property_value_register.has_value()) {
// 5. Let propertyKey be ? ToPropertyKey(propertyNameValue).
// FIXME: This does ToPropertyKey out of order, which is observable by Symbol.toPrimitive!
generator.emit<Bytecode::Op::GetByValue>(*computed_property_value_register);
} else {
// 3. Let propertyKey be StringValue of IdentifierName.
auto identifier_table_ref = generator.intern_identifier(verify_cast<Identifier>(member_expression.property()).string());
generator.emit<Bytecode::Op::GetById>(identifier_table_ref);
}
} else {
TRY(member_expression.object().generate_bytecode(generator));
generator.emit<Bytecode::Op::Store>(this_reg);
if (member_expression.is_computed()) {
@ -1546,6 +1572,8 @@ Bytecode::CodeGenerationErrorOr<void> CallExpression::generate_bytecode(Bytecode
auto identifier_table_ref = generator.intern_identifier(verify_cast<Identifier>(member_expression.property()).string());
generator.emit<Bytecode::Op::GetById>(identifier_table_ref);
}
}
generator.emit<Bytecode::Op::Store>(callee_reg);
} else {
// FIXME: this = global object in sloppy mode.

39
Userland/Libraries/LibJS/Bytecode/Generator.cpp
View file

@ -151,6 +151,44 @@ CodeGenerationErrorOr<void> Generator::emit_load_from_reference(JS::ASTNode cons
}
if (is<MemberExpression>(node)) {
auto& expression = static_cast<MemberExpression const&>(node);
// https://tc39.es/ecma262/#sec-super-keyword-runtime-semantics-evaluation
if (is<SuperExpression>(expression.object())) {
// 1. Let env be GetThisEnvironment().
// 2. Let actualThis be ? env.GetThisBinding().
// NOTE: Whilst this isn't used, it's still observable (e.g. it throws if super() hasn't been called)
emit<Bytecode::Op::ResolveThisBinding>();
Optional<Bytecode::Register> computed_property_value_register;
if (expression.is_computed()) {
// SuperProperty : super [ Expression ]
// 3. Let propertyNameReference be ? Evaluation of Expression.
// 4. Let propertyNameValue be ? GetValue(propertyNameReference).
TRY(expression.property().generate_bytecode(*this));
computed_property_value_register = allocate_register();
emit<Bytecode::Op::Store>(*computed_property_value_register);
}
// 5/7. Return ? MakeSuperPropertyReference(actualThis, propertyKey, strict).
// https://tc39.es/ecma262/#sec-makesuperpropertyreference
// 1. Let env be GetThisEnvironment().
// 2. Assert: env.HasSuperBinding() is true.
// 3. Let baseValue be ? env.GetSuperBase().
emit<Bytecode::Op::ResolveSuperBase>();
// 4. Return the Reference Record { [[Base]]: baseValue, [[ReferencedName]]: propertyKey, [[Strict]]: strict, [[ThisValue]]: actualThis }.
if (computed_property_value_register.has_value()) {
// 5. Let propertyKey be ? ToPropertyKey(propertyNameValue).
// FIXME: This does ToPropertyKey out of order, which is observable by Symbol.toPrimitive!
emit<Bytecode::Op::GetByValue>(*computed_property_value_register);
} else {
// 3. Let propertyKey be StringValue of IdentifierName.
auto identifier_table_ref = intern_identifier(verify_cast<Identifier>(expression.property()).string());
emit<Bytecode::Op::GetById>(identifier_table_ref);
}
} else {
TRY(expression.object().generate_bytecode(*this));
if (expression.is_computed()) {
@ -168,6 +206,7 @@ CodeGenerationErrorOr<void> Generator::emit_load_from_reference(JS::ASTNode cons
"Unimplemented non-computed member expression"sv
};
}
}
return {};
}
VERIFY_NOT_REACHED();

1
Userland/Libraries/LibJS/Bytecode/Instruction.h
View file

@ -76,6 +76,7 @@
O(PutById) \
O(PutByValue) \
O(ResolveThisBinding) \
O(ResolveSuperBase) \
O(Return) \
O(RightShift) \
O(ScheduleJump) \

25
Userland/Libraries/LibJS/Bytecode/Op.cpp
View file

@ -530,6 +530,26 @@ ThrowCompletionOr<void> ResolveThisBinding::execute_impl(Bytecode::Interpreter&
return {};
}
// https://tc39.es/ecma262/#sec-makesuperpropertyreference
ThrowCompletionOr<void> ResolveSuperBase::execute_impl(Bytecode::Interpreter& interpreter) const
{
auto& vm = interpreter.vm();
// 1. Let env be GetThisEnvironment().
auto& env = verify_cast<FunctionEnvironment>(*get_this_environment(vm));
// 2. Assert: env.HasSuperBinding() is true.
VERIFY(env.has_super_binding());
// 3. Let baseValue be ? env.GetSuperBase().
auto base_value = TRY(env.get_super_base());
// 4. Let bv be ? RequireObjectCoercible(baseValue).
interpreter.accumulator() = TRY(require_object_coercible(vm, base_value));
return {};
}
ThrowCompletionOr<void> GetNewTarget::execute_impl(Bytecode::Interpreter& interpreter) const
{
interpreter.accumulator() = interpreter.vm().get_new_target();
@ -1383,6 +1403,11 @@ DeprecatedString ResolveThisBinding::to_deprecated_string_impl(Bytecode::Executa
return "ResolveThisBinding"sv;
}
DeprecatedString ResolveSuperBase::to_deprecated_string_impl(Bytecode::Executable const&) const
{
return "ResolveSuperBase"sv;
}
DeprecatedString GetNewTarget::to_deprecated_string_impl(Bytecode::Executable const&) const
{
return "GetNewTarget"sv;

13
Userland/Libraries/LibJS/Bytecode/Op.h
View file

@ -1130,6 +1130,19 @@ public:
void replace_references_impl(Register, Register) { }
};
class ResolveSuperBase final : public Instruction {
public:
explicit ResolveSuperBase()
: Instruction(Type::ResolveSuperBase)
{
}
ThrowCompletionOr<void> execute_impl(Bytecode::Interpreter&) const;
DeprecatedString to_deprecated_string_impl(Bytecode::Executable const&) const;
void replace_references_impl(BasicBlock const&, BasicBlock const&) { }
void replace_references_impl(Register, Register) { }
};
class GetNewTarget final : public Instruction {
public:
explicit GetNewTarget()